The seeder (1) has a hitching frame (4) connected to a chassis (2) using an upper crosspiece (9) and hooking plates (10). An upper link pin (6) is extended in bottom and both sides of a vertical median plane (11). The hooking plates are extended near a mid plane (13) extending at mid-distance between a median vertical plane and a underlying plane (14), where the mid plane and the underlying plane are parallel to the median vertical plane. The hooking plates are extended near an additional seed unit (19).